Prosecutors acting against drivers who caused fatal crashes have been told to charge defendants with more serious offences, ensuring that they will face a prison sentence if found guilty.

The Crown Prosecution Service Inspectorate (HMCPSI) said in a review of the decision-making, conduct and prosecution by the Crown Prosecution Service (CPS) that some cases could have been prosecuted with the more serious charge of causing death by dangerous driving rather than the lesser charge of careless driving, which does not carry a prison sentence.

A conviction for causing death by dangerous driving carries a maximum 14-year prison sentence.

The review said: “Although inspectors would not go so far as to describe them as ‘wrong’, these cases could also justify being prosecuted as causing death by dangerous driving, rather than the careless driving selected.

"It would seem that in these cases prosecutors tended to select the lower, rather than the higher, of the feasible charges.”

The inspectors also discovered cases where prosecutors had felt there was insufficient evidence to prosecute, but which the inspectors considered could have resulted in a successful careless driving prosecution.

Stephen Wooler, chief inspector of the CPS, said: “There remain a few difficult cases where the evidence could have justified a prosecution or the selection of a more serious charge.

"Recent legislation and expansion of the guidance on these offences make these issues less significant in the future.”

The HMCPSI has now called for the CPS to provide prosecutors with more guidance on what constitutes dangerous driving.

The review comes just three months after the new offence of causing death by careless driving was introduced.

It also comes six months after new tougher guidelines for sentencing drivers found guilty of driving offences resulting in a fatality, including the new offence of causing death by careless driving.

This should help prosecutors find middle ground when they are unsure whether the more serious charge would be successful.

In a statement the CPS said: “There remains great public interest in how fatal road traffic collisions are dealt with and particular concern to see those whose driving causes the death of others being suitably prosecuted and punished.”